Correlation of carriers in communications

Abstract

Methods, apparatus, and systems for carrier aggregation in sidelink communications are disclosed. The method comprises: determining, at a first node, a candidate carrier set for aggregation; selecting one or more candidate carriers from the candidate carrier set as one or more component carriers for carrier aggregation based on the correlation between the carriers; and transmitting or receiving on the one or more component carriers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 457,273, entitled “CORRELATION OF CONGESTION AND CHANNEL CONDITIONS BETWEEN TWO CARRIERS FOR PACKET DUPLICATION IN SIDELINK COMMUNICATION” and filed on April 5, 2023, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] Apparatuses and methods consistent with the present disclosure relate generally to communication, and more specifically to methods, systems, and devices for performing carrier aggregation in sidelink communication in a communication network. BACKGROUND

[0003] Sidelink (SL) communication is used in 3GPP radio interfaces to allow two or more wireless devices or user equipments (UEs) to communicate directly between them. This can happen within the coverage of a cellular network, outside the coverage of a cellular network, or even within a partial coverage of a cellular network where only one of the two UEs is within the coverage of the network. Direct device-to-device communication uses the PC5 interface.

[0004] Sidelink communication is used for Vehicle-to-Everything (V2X) applications, also known as V2X. SL devices can use various radio access technologies (RATs), such as Long Term Evolution (LTE) SL, Next Radio (NR) SL, or both, for transmission and reception.

[0005] Many radio interface technologies use carrier aggregation. The main principle of carrier aggregation is to transmit multiple packets in parallel on different carriers. A "carrier" is a waveform that conveys a physical channel. Carrier aggregation is widely deployed in radio communication systems, typically for wireless broadband applications. Carrier aggregation can be implemented by transmitting or receiving on multiple carriers simultaneously, thereby aggregating the bandwidth of each carrier to allow higher bandwidth transmission or reception. Each aggregated carrier can be referred to as a "component carrier". Not all available carriers can be considered for aggregation; carriers that can be considered for aggregation can be referred to as "candidate carriers". Examples of such technologies in terrestrial radio systems are 3GPP High-Speed Packet Access (HSPA) and 3GPP Long-Term Evolution (LTE), where carrier aggregation increases the data transfer throughput on the radio interface between infrastructure nodes and mobile nodes. 3GPP typically denotes this interface as the Uu interface.

[0006] In addition to throughput enhancement, carrier aggregation can also be used for reliability and latency enhancement. The basic idea is to duplicate (e.g., duplicate two times or duplicate multiple times) packets on parallel carriers. Packet duplication is useful for services and deployments that require high reliability and low latency, or if reliability and latency is an issue.

[0007] One example of such a deployment is Sidelink (SL), where nodes are able to communicate directly with each other, without the need for continuous connection to a control entity on the infrastructure side, as opposed to e.g. traditional cellular communication such as mobile phone systems. In the absence of continuous connection to a central control entity, SL resource allocation cannot be performed in a coordinated or centralized manner. Therefore, nodes perform autonomous or local resource allocation based on resource sensing independent of each other in a distributed manner. Such distributed operation is typically less complex than a centralized scheme, but it introduces uncertainty in communication reliability and latency.

[0008] To address these issues, 3GPP has specified carrier aggregation for SL communication in the LTE radio interface standard, such as in Technical Specification 36.213 and Technical Specification 36.321. 3GPP typically denotes this interface as the SL or PC5 interface. It is currently being discussed to address the same issues in the 3GPP NR radio interface by specifying SL carrier aggregation in the scope of 3GPP Release 18 work item. SUMMARY

[0009] According to some embodiments of the present disclosure, a method for carrier aggregation in sidelink communication is provided. The method comprises: determining, at a first node, a set of candidate carriers for aggregation; selecting, based on a correlation between carriers, one or more candidate carriers from the set of candidate carriers as one or more component carriers for carrier aggregation; and transmitting or receiving on the one or more component carriers.

[0010] According to some embodiments of the present disclosure, a first node is provided. The first node comprises: a memory configured to store instructions; and a processor configured to execute the instructions stored in the memory to: determine a set of candidate carriers for aggregation; select, based on a correlation between carriers, one or more candidate carriers from the set of candidate carriers as one or more component carriers for carrier aggregation; and transmit or receive on the one or more component carriers.

[0011] According to some embodiments of the present disclosure, a non-transitory computer-readable medium storing instructions executable by one or more processors of a first node in a communication network to perform a method is provided. The method comprises: determining, at the first node, a set of candidate carriers for aggregation; selecting, based on a correlation between carriers, one or more candidate carriers from the set of candidate carriers as one or more component carriers for carrier aggregation; and transmitting or receiving on the one or more component carriers.

[0012] According to some embodiments of the present disclosure, a method for carrier correlation detection is provided. The method comprises: determining a correlation of signals between carriers in a set of carriers; creating a resource matrix for each carrier in the set of carriers; and obtaining a correlation metric based on the resource matrix.

[0013] According to some embodiments of the present disclosure, a first node is provided. The first node comprises: a memory configured to store instructions; and a processor configured to execute the instructions stored in the memory to: determine a correlation of signals between carriers in a set of carriers; create a resource matrix for each carrier in the set of carriers; and obtain a correlation metric based on the resource matrix.

[0014] According to some embodiments of the present disclosure, a non-transitory computer-readable medium storing instructions executable by one or more processors of a first node to perform a method is provided. The method comprises: determining a correlation of signals between carriers in a set of carriers; creating a resource matrix for each carrier in the set of carriers; and obtaining a correlation metric based on the resource matrix. BRIEF DESCRIPTION OF DRAWINGS

[0015] [Figure 1 ] Figure 1 is a diagram illustrating a device type for dynamic co-existence of a first sidelink communication and a second sidelink communication, consistent with some embodiments of the present disclosure.

[0016] [ Figure 2 ] Figure 2 is a flowchart of a method for carrier aggregation in sidelink communications, consistent with some embodiments of the present disclosure.

[0017] [ Figure 3 ] Figure 3 is a flowchart of a method for carrier correlation detection, consistent with some embodiments of the present disclosure.

[0018] [ Figure 4 ] Figure 4 is a block diagram of a node, consistent with some embodiments of the present disclosure. DETAILED DESCRIPTION

[0019] Reference will now be made in detail to the example embodiments, examples of which are illustrated in the accompanying drawings. Respective drawings are referenced in the following description, in which the same numbers indicate the same or similar elements unless otherwise indicated. The implementations set forth in the following description of example embodiments are not meant to be

[0020] Interface between LTE SL module and NR SL module

[0021] As part of the 3GPP discussions, device type A is defined as a device that includes both an LTE SL module and an NR SL module, where the NR SL module is able to receive information from the LTE SL module. To study the feasibility of dynamic resource sharing as a possible solution for co-existence, for device type A, the NR SL module uses sensing and resource reservation information shared by the LTE SL module.

[0022] Figure 1 is a diagram illustrating a device type for dynamic co-existence of a first SL communication and a second SL communication, consistent with some embodiments of the present disclosure. See Figure 1At least three types (Type A, Type B, and Type C) of devices are considered in this disclosure. Type A devices include modules for first SL communications and modules for second SL communications. Type B devices include only modules for first SL communications. Type C devices include only modules for second SL communications. For example, in one embodiment, Type A devices include both LTE SL modules and NR SL modules; Type B devices include only NR SL modules; and Type C devices include only LTE SL modules.

[0023] Current schemes independently select SL resources on each carrier (e.g., as described in Technical Specification 36.213 and Technical Specification 36.321). The resource selection procedure includes sensing procedures and rules for resource exclusion that are performed in a carrier-specific manner. The resource selection procedure uses Reference Signal Received Power (RSRP) measurements, Received Signal Strength Indicator (RSSI) measurements, Channel Busy Ratio (CBR) estimates, and Channel Occupancy Ratio (CR) estimates.

[0024] 3GPP Release 15 LTE-V2X PC5 Mode 4 supports SL carrier aggregation. Multiple sidelink carriers (i.e., multiple V2X channels) can be used to increase throughput and / or improve reliability. To increase throughput, multiple Medium Access Control (MAC) Protocol Data Units (PDUs) can be transmitted on multiple sidelink carriers. To improve reliability, packet duplication can be supported, where the same PDCP packet is transmitted on multiple sidelink carriers. For example, 3GPP Technical Specification 36.321 clause 5.14.1.5 specifies a transmission carrier selection or carrier reselection procedure to select or reselect a sidelink carrier for transmission based on the measured CBR for each sidelink carrier. In the transmission carrier selection / reselection procedure, a transmission UE considers a sidelink carrier as a candidate sidelink carrier if the measured CBR of the sidelink carrier is below a configured or preconfigured CBR threshold (associated with a priority). The transmission UE then selects one or more sidelink carriers among the candidate sidelink carriers in increasing order of CBR, starting from the lowest CBR. The transmission UE selects how many sidelink carriers to leave to UE implementation based on UE capability. For each selected sidelink carrier, LTE SL carrier aggregation reuses the sensing and resource selection procedure from 3GPP Release 14 LTE-V2X PC5 Mode 4. That is, the UE independently selects resources on each involved carrier based on the Release 14 sensing and resource selection procedure. The Release 15 resource selection procedure takes into account the capability of the transmission UE regarding whether it can transmit on multiple carriers at a time, such that the resource selection procedure will not select resources for transmission that violate the capability of the transmission UE. The same sidelink carrier is used at least until the procedure triggers transmission carrier reselection.

[0025] A drawback of the current approach is that two or more carriers can be correlated, as the allocation for different carriers is performed independently from each other, which can negatively impact the carrier aggregation gain. For example, if two carriers are experiencing the same type of congestion, any transmission on the two or more carriers will be affected by that same congestion. In this case, the gain of carrier aggregation (e.g., packet duplication) will be lower than in the case where the carriers experience uncorrelated congestion.

[0026] The disclosed embodiments improve current solutions by identifying the correlation between two or more carriers and using this information in resource allocation and selection. One benefit is higher gain in terms of packet duplication gain, such as higher reliability and lower latency, and higher gain in terms of throughput gain, as the channel conditions, e.g. congestion, propagation, etc. are not correlated or they are less correlated.

[0027] Some embodiments described herein provide methods and apparatuses for identifying correlation between two or more carriers in a carrier aggregation deployment, exchanging correlation information with a node, and selecting resources based on the correlation information. The method can be applied to any wireless communication system using carrier aggregation, but in the rest of this disclosure, the method is exemplified using a terrestrial mobile radio communication system supporting SL communication, such as 3GPP LTE and / or NR radio access technology, but is not limited thereto.

[0028] For brevity, two nodes are used herein to exemplify the method, but any application of the method is not limited to the simplified use case. It should be appreciated that the skilled person can generalize the disclosed embodiments to be applied to multiple nodes. Likewise, the method is exemplified using one-way communication between the nodes, but is not limited thereto, but it can be applied to two-way communication, i.e. two communication directions between two nodes, or there can be separate procedures occurring, e.g. the method can be applied to one direction and not to the other.

[0029] In one embodiment, a first node, also referred to herein as a transmitting node (although such a node can comprise both transmission and reception capabilities, indicates to a second node, also referred to herein as a receiving node (although such a node can comprise both reception and transmission capabilities, the start of a carrier correlation detection procedure. The indication can be transmitted over the air from the transmitting node to the receiving node, e.g. by means of populating radio parameters, indicators or fields in e.g. radio interface messages, radio protocol data unit headers or physical layer fields / control information. The indication can convey information about a set of two or more carriers, e.g. their identity and / or frequency, to allow the receiving node to perform e.g. correlation of propagation paths and traffic conditions / activity on the carriers.

[0030] In another embodiment, the receiving node can indicate to the transmitting node the start of the carrier correlation detection procedure. The indication can be transmitted over the air from the receiving node to the transmitting node in the same way and with similar data and format as in the above-described embodiment.

[0031] In another embodiment, a node (transmitting node or receiving node) can restart the carrier relevance detection procedure. Restarting the carrier relevance detection procedure can address use cases where propagation and traffic conditions are time-varying. For example, a timer can be started upon indication of the carrier relevance detection procedure, and the carrier relevance detection procedure can be restarted upon expiry of the timer. The timer value can be given, for example, as a stored configuration in the node and provided by a controlling network entity, as a stored configuration in the node and provided by another node, pre-configured in a Subscriber Identity Unit (SIM / USIM), pre-configured in a Universal Integrated Circuit Card (UICC), or hard-coded in the software of the node. In another example, the restart of the carrier relevance detection procedure can be triggered based on an event detected by the transmitting node or the receiving node. Example events can include a change in one or more propagation or traffic metrics (e.g., RSSI, CBR) between two or more time instances that exceeds one or more configured or pre-configured thresholds. In one example, the detection event can be performed within a time duration that starts upon initiation of the carrier relevance detection procedure. In another example, the configured timer value can be scaled depending on the speed of the involved node or the rate of observed radio environment changes.

[0032] At the start or restart of the carrier correlation detection procedure and upon receiving its associated information, the transmitting node transmits signals on the above-mentioned set of carriers for correlation detection in the receiving node. Such transmitted signals can be, for example, SL transmissions with a predetermined payload and / or reference signals such as Channel State Information Reference Signals (CSI-RS). Another alternative can use Demodulation Reference Signals (DM-RS) transmitted together with the Physical Sidelink Control Channel (PSCCH) or the Physical Sidelink Shared Channel (PSSCH) for correlation detection (RSRP measurements are based on DM-RS). The predetermined payload and its format can be given, for example, as a stored configuration in the node and provided by the controlling network entity, as a stored configuration in the node and provided by another node, preconfigured in the SIM / USIM, preconfigured in the UICC, or hard-coded in the software of the node. The selection of the transmitted signals (e.g., using a predetermined payload or CSI-RS) can also be decided by the transmitting node and / or the receiving node and can communicate the selection under the indication of the start and restart of the carrier correlation detection procedure.

[0033] Upon starting or restarting the carrier correlation detection procedure and receiving its associated information, the receiving node receives signals, e.g. predetermined payload or CSI-RS, on the carriers. The receiving node evaluates the correlation of the signals used by the transmitting node across different carriers. The correlation can be evaluated, for example, in terms of: received energy, channel impulse response, history of CBR measurements, history of RSSI measurements, history of reserved resources, other physical layer measurements, history of Channel Occupancy Ratio (CR) measurements, history of CSI report values, history of L3 filtered SL-RSRP (for transmission power determination), history of Acknowledgement (ACK) / Negative Acknowledgement (NACK) ratio, history of Listen-Before Talk (LBT) failure rate (e.g. if it is operating in unlicensed band), history of persistent LBT failures, history of radio link failures, history of beam recovery / re-alignment (e.g. if operating with narrow beams in FR2 carriers). For each carrier, the receiving node creates a time and frequency resource matrix as an output of its own sensing procedure, and then obtains a correlation measure representing the correlation between the carriers. The generated matrix can be one or a combination of the embodiments described below. It should be noted that the term “matrix” is used as a broad term herein without implying any limitation in terms of specific storage or graphical representation. While some of the examples below refer to the term “matrix” or “binary matrix”, the examples can also be described by using, for example, direct calculations or formulas without necessarily referring to the term “matrix” or “binary matrix”.

[0034] In another embodiment, the correlation information can be computed using a binary matrix in which each matrix element comprises binary information (e.g., a "0" value or a "1" value) if activity is detected or not detected at the receiving node in each time / frequency resource (e.g., each time slot or subchannel). Activity detection can be made based on, for example, RSRP, RSSI, Signal to Noise and Interference Ratio (SINR), or energy detection. In one embodiment, activity detection can use one or more thresholds. For example, the receiving node can compare a measured value in a time slot, subchannel, or other type of frequency and time resource to a threshold. The threshold can be given, for example, as a stored configuration in the node and provided by a controlling network entity, as a stored configuration in the node and provided by another node, preconfigured in a SIM / USIM, preconfigured in a UICC, or hard-coded in the node's software. If the obtained measured value in the time slot or subchannel (e.g., RSRP or RSSI) is below the threshold, the matrix element for the respective time slot or subchannel is populated with a "0" value, otherwise it is populated with a "1" value.

[0035] In another embodiment, the correlation information can be computed using a binary matrix in which each matrix element comprises identification information to indicate whether the identity activated in the carrier matches in time and frequency. Each matrix element can provide information about the time and frequency resources in which the receiving node is able to receive a signal from the transmitting node and identify its carrier. The identification information can be used to address use cases in which the carrier can be subject to, for example, severe frequency-selective fading or co-channel interference (i.e., the received signal is contaminated by another similar kind of information-bearing signal from a node other than the first node) or other undesirable events such as jamming (i.e., intentional interference), affecting the propagation path and signal delivery.

[0036] In another embodiment, the correlation information can be computed using a numerical matrix in which each matrix element is, for example, an integer value or a floating point number. The matrix elements can be represented as code points in a fixed size bit combination to identify the correlation of signals transmitted in time and frequency resources. One example of this embodiment is to compute the cross-correlation function of the sampled channel impulse responses from two carriers. The result of the cross-correlation computation is a general measure that can describe the similarity between data sequences and signals (in this case, the channel impulse responses of different carriers). It can be used as a measure to identify how strongly the propagation paths on different carriers are correlated. The obtained correlation values can be filled into the matrix elements corresponding to the carriers.

[0037] In another embodiment, the correlation information can be computed based on the results of decoding data that has been duplicated (PDCP duplication) across multiple carriers by the transmitting UE. If the same data is sent across multiple carriers at about the same time, the correlation of the decoding results across the carriers can be determined. For example, if a recurring interfering signal equally affects all carriers, a high correlation of the decoding results will most likely be observed. On the other hand, if the interfering signal only affects an appropriate subset of the carriers, the correlation of the decoding results between the carriers that are affected by the interference and the carriers that are not affected by the interference will most likely be low. These decoding results can be determined by the receiving UE. If Hybrid Automatic Repeat Request (HARQ) feedback is used, the decoding results also become visible to the transmitting UE.

[0038] In the case of two carriers, the diagonal of the matrix, i.e. the elements (1,1) and (2,2), represent the autocorrelation, i.e. the correlation of the signal with itself and the result of a perfect correlation, while the elements (2,1) and (1,2) represent the cross-correlation between the two different carriers and yield the same numerical value in both elements. A high correlation value indicates a high correlation between the carriers, while a low integer value indicates a low correlation between the carriers.

[0039] In another embodiment, after obtaining the cross-correlation between the carriers, the receiving node can share the correlation information with the transmitting node. The correlation information can be transferred from the receiving node to the transmitting node over the air, for example, by filling radio parameters, indicators or fields in, for example, radio interface messages, radio protocol data unit headers, physical layer fields, or as an octet string included in a radio protocol (for example, as a transparent container).

[0040] The transmitted correlation information can be the entire matrix representation, e.g. the internal representation of the data of the receiving node, or a compressed version of the matrix to reduce the overhead. For example, in case of a channel impulse response cross-correlation between two carriers, the correlation matrix is a symmetric 2x2 matrix, because the elements (1,2) and (2,1) have the same value, because the correlation values are calculated in the same way, and the values on the diagonal, i.e. elements (1,1) and (2,2), are not of interest for the transmitting node, because they are the result of self-correlation and not cross-correlation. This means that the matrix values on the diagonal can be removed and only one of the elements (1,2) or (2,1) can be communicated.

[0041] The correlation values can be transmitted, for example, as integer values or floating point numbers, which are represented as code points in a fixed size bit combination. The correlation values can also be compressed into one bit, which is used to indicate whether a carrier is correlated or not. For example, the correlation value can be compared to a threshold value. If the correlation value is higher than the threshold value, the bit can be set to "1", otherwise it can be set to "0". One possible interpretation is that the bit value "1" indicates a correlated carrier, while the bit value "0" indicates an uncorrelated or sufficiently uncorrelated carrier.

[0042] In another embodiment, the transmitting node can use the correlation information in resource selection, resource reselection, carrier selection or carrier reselection. For example, if two carriers are strongly correlated, one of them can be excluded from the transmission occasion, e.g. until the correlation between the carriers is sufficiently low.

[0043] In another embodiment, the receiving node can provide a report containing the raw or filtered version of the physical layer measurements, which are then used by the transmitting node to calculate the correlation information. This option can require more signaling, but can be preferred in case the transmitting node has more computational and decision making capabilities than the receiving node, e.g. if the transmitting node is an access point considering measurements from multiple other nodes for deciding on carrier selection or carrier reselection.

[0044] In another embodiment, the receiving node can share recommended carrier information with the transmitting node based on the cross-correlation between the carriers. For example, the receiving node can share one or more carrier indices with a cross-correlation value below a threshold value.

[0045] In another embodiment, the transmitting node can use its sensing information and the information shared from the receiving node in resource selection, resource reselection, carrier selection or carrier reselection.

[0046] In another embodiment, other functions for computing similarity and / or difference of two matrices can be used instead of the cross-correlation function. For example, cosine similarity and / or distance (e.g., L-0 norm, L-1 norm, L-2 norm, etc.) between two matrices can be used. One or more similarity functions can be used.

[0047] In another embodiment, whether a different RAT can be detected can be used to implement any of the embodiments described herein. For example, whether LTE can be detected can be used to enable the procedure for LTE NR carrier aggregation.

[0048] In another embodiment, a priority can be used to evaluate whether to enable any of the embodiments described herein. One or more priority thresholds can also be used. Examples of priorities can include 5G Quality of Service Identifier (5QI) priority, Quality of Service Class Indicator (QCI) priority (used in LTE), Proximity Service (ProSe) Per-Packet Priority (PPPP), L1 / L2 priority, or any other priority related to Quality of Service or application priority.

[0049] In another embodiment, any of the information provided, measured, and / or computed can be forwarded by additional nodes to perform any of the embodiments described herein.

[0050] Figure 2 is a flowchart of a method 200 for carrier aggregation in sidelink communications consistent with some embodiments of the present disclosure. The method 200 can be performed by a node in a communication system, e.g., by a UE in sidelink communications. For purposes of illustration, assume that the method 200 is performed in a node that includes an LTE SL module and an NR SL module.

[0051] The method 200 includes a step 202 of determining, at a first node, a set of candidate carriers for aggregation. In some embodiments, the first node can consider a carrier as a candidate carrier if the measured CBR of the carrier is below a configured or preconfigured CBR threshold. The first node can then select one or more carriers among the candidate carriers based on an increasing order of CBRs starting from the lowest CBR.

[0052] The method 200 comprises: selecting, from the set of candidate carriers, one or more candidate carriers as one or more component carriers for carrier aggregation, step 204. In some embodiments, selecting the one or more candidate carriers can be performed based on excluding one or more carriers having a high correlation with another carrier or carriers. In some embodiments, determining the correlation between carriers can be performed based on correlation information received at the first node. In some embodiments, the method 200 can further comprise receiving a communication comprising the correlation information from the second node, wherein the communication comprises any of a radio interface message, a radio protocol data unit header, a physical layer field, or physical layer control information.

[0053] The method 200 comprises: transmitting or receiving on the one or more component carriers, step 206. Once the component carriers are selected, the first node can perform carrier aggregation by transmitting or receiving on the selected component carriers. Transmitting data on the selected one or more carriers involves scheduling in which the node decides which carrier to use for transmitting data units in the transmitter buffer of the node. The decision can be made considering all carriers within the selected set, randomly and uniformly or in a round-robin order, without any priority, for example, to achieve uniform sharing of traffic load among the carriers. The decision can also involve determining a transmission sequence, for example, based on data unit priorities. Receiving on the one or more carriers within the selected set comprises receiving control information such as channel state information and data unit priorities transmitted in data unit headers and / or on separate physical layer control fields, as well as receiving data unit payloads. Transmitting and receiving data can also include retransmissions requested by the receiver if a transmission attempt fails.

[0054] In some embodiments, the method 200 can further comprise performing a carrier correlation detection procedure. In some embodiments, the carrier correlation detection procedure can be performed upon receiving, by the first node, an indication to start the carrier correlation detection procedure. In some embodiments, the indication can comprise information related to a second set of carriers allowing the first node to perform the carrier correlation detection procedure on the second set of carriers. In some embodiments, the method 200 can further comprise receiving a communication comprising the indication to start the carrier correlation detection procedure from the second node, wherein the communication comprises any of a radio interface message, a radio protocol data unit header, a physical layer field, or physical layer control information.

[0055] In some embodiments, the method 200 can further include resuming the carrier correlation detection procedure. In some embodiments, the resuming can be triggered based on an event detected by the first node. In some embodiments, the event can include one or more of a change in a traffic metric, a change in a traffic metric over a predetermined time period, a change in a traffic metric over a predetermined time period that exceeds a configured or preconfigured threshold, a change in multiple traffic metrics, a change in multiple traffic metrics over a predetermined time period, or a change in multiple traffic metrics each exceeding a configured or preconfigured threshold over a predetermined time period. In some embodiments, the traffic metric can include one or more of a received signal strength indicator or a channel busy ratio. In some embodiments, the predetermined time period can start at the start of the carrier correlation detection procedure. In some embodiments, the predetermined time period can be scaled depending on a speed of the first node or a rate of observed radio environment changes.

[0056] In some embodiments, the method 200 can further include starting a timer when the carrier correlation detection procedure starts, and resuming the carrier correlation detection procedure when the timer expires. In some embodiments, a duration of the timer can be based on any of a stored configuration in the first node provided by a controlling network entity, a stored configuration in the first node provided by another node, a pre-configuration in a subscriber identity unit, a pre-configuration in a universal integrated circuit card, or a hardcoding in the first node.

[0057] Figure 3 is a flowchart of a method 300 for carrier correlation detection consistent with some embodiments of the present disclosure. The method 300 can be performed by a node in a communication system, for example, by a UE in a sidelink communication. For purposes of illustration, assume that the method 300 is performed in a node that includes an LTE SL module and an NR SL module, although the node can include any other module(s).

[0058] The method 300 includes a step 302 of determining a correlation of signals between carriers in a set of carriers. In some embodiments, the method 300 can further include receiving one or more signals in the set of carriers, where the one or more signals include a predetermined payload or a reference signal. In some embodiments, the predetermined payload can include any of a stored configuration in the first node provided by a controlling network entity, a stored configuration in the first node provided by another node, a pre-configuration in a subscriber identity unit, a pre-configuration in a universal integrated circuit card, or a hardcoding in the first node. In some embodiments, the reference signal can include any of a channel state information reference signal or a demodulation reference signal with one of a physical sidelink control channel or a physical sidelink shared channel.

[0059] In some embodiments, determining the correlation of the signal can be based on any one of: received energy, a channel impulse response, a history of channel busy ratio measurements, a history of received signal strength indicator measurements, a history of reserved resources, a history of channel occupancy ratio measurements, a history of channel state information report values, a history of L3 filtered sidelink received signal reference power measurements, a history of one or more of acknowledgement ratios or negative acknowledgement ratios, a listen before talk (LBT) failure rate, a history of persistent LBT failures, a history of radio link failures, or a history of one or more of beam recovery or beam realignment.

[0060] The method 300 includes step 304, creating a resource matrix for each carrier in the set of carriers. In some embodiments, creating the resource matrix can include creating a time and frequency resource matrix based on sensing information determined by the first node.

[0061] The method 300 includes step 306, obtaining a correlation metric based on the resource matrix. In some embodiments, obtaining the correlation metric can include using a binary matrix to calculate the correlation metric, and each matrix element of the resource matrix can be composed of binary information if activity is detected or not detected at the first node in each of one or more of the time resources or frequency resources. In some embodiments, whether activity is detected at the first node can be based on any one or more of: received signal reference power, received signal strength indicator, signal to noise and interference ratio, or energy detection.

[0062] In some embodiments, the method 300 can further include comparing a measured value of each of one or more of the time resources or frequency resources to a threshold value. If the measured value is below the threshold value, the matrix element for the corresponding resource can be a “0” value. If the measured value is equal to or above the threshold value, the matrix element for the corresponding resource can be a “1” value. In some embodiments, the threshold value can include any one of: a stored configuration in the first node provided by a controlling network entity, a stored configuration in the first node provided by another node, a pre-configuration in a subscriber identity unit, a pre-configuration in a universal integrated circuit card, or a hardcoding in the first node.

[0063] In some embodiments, obtaining the correlation metric can include using a binary matrix to calculate the correlation metric, and each matrix element of the resource matrix can be composed of identification information to provide information about time and frequency resources in which the first node is able to receive a signal from the second node and identify its carrier.

[0064] In some embodiments, obtaining the correlation measure can include using a numerical matrix to compute the correlation measure, and each matrix element of the resource matrix can identify a correlation of a signal transmitted in a time and frequency resource. In some embodiments, each matrix element can be an integer value or a floating point value. In some embodiments, each matrix element can be a correlation value obtained based on a similarity of channel impulse responses of different carriers.

[0065] In some embodiments, obtaining the correlation measure can include computing the correlation measure based on a result of decoding data that has been replicated across multiple carriers in the set of carriers. In some embodiments, a high value in the matrix can indicate a high correlation between carriers; and a low value in the matrix can indicate a low correlation between carriers.

[0066] In some embodiments, the method 300 can further include receiving the correlation measure at the first node from the second node. In some embodiments, the method 300 can further include sharing the correlation measure from the first node to the second node. In some embodiments, the receiving or sharing can include any of populating a radio parameter, an indicator, or a field in a radio interface message; populating a field in a radio protocol data unit header; populating a physical layer field; or receiving an octet string contained in a radio protocol. In some embodiments, the receiving or sharing can include receiving the correlation measure as a matrix or a compressed matrix. In some embodiments, the receiving or sharing can include receiving the correlation measure as an integer value or a floating point number represented as a code point in a fixed size bit combination. In some embodiments, the receiving or sharing can include receiving the correlation measure as a single bit to indicate whether carriers are correlated. In some embodiments, the receiving or sharing can further include comparing the correlation measure to a threshold to determine a value of the single bit; and if the correlation is above the threshold, the value of the single bit can be set to “1”.

[0067] In some embodiments, the method 300 can further include indicating that one or more of the carriers are excluded from a transmission occasion if the correlation measure indicates that the one or more carriers are strongly correlated. In some embodiments, the method 300 can further include determining carriers having a correlation value below a threshold; and sharing the determined carriers with the second node.

[0068] Node

[0069] Figure 4is a block diagram of a node 400 consistent with some embodiments of the present disclosure. The node 400 can be a Type-A, Type-B, Type-C, or any other type of UE. The node 400 can be installed in a mobile vehicle or in a fixed location. The node 400 can take any form including but not limited to a vehicle, a component installed in a vehicle, a road-side unit, a laptop computer, a wireless terminal including a handset, a wireless handheld device, or a wireless personal device, or any other form. In the foregoing description, any reference to a UE performing certain functions can be replaced with a node performing the same functions without changing the operation or functionality of any element described herein.

[0070] Referring to Figure 4 The node 400 can include an antenna 402 that can be used to transmit electromagnetic signals to and receive electromagnetic signals from a base station or other UEs. The antenna 402 can include one or more antenna elements and can enable different input-output antenna configurations, such as Multiple Input Multiple Output (MIMO) configurations, Multiple Input Single Output (MISO) configurations, and Single Input Multiple Output (SIMO) configurations. In some embodiments, the antenna 402 can include a plurality of (e.g., tens or hundreds of) antenna elements and can enable multi-antenna functionality such as beamforming. In some embodiments, the antenna 402 is a single antenna.

[0071] The node 400 can include a transceiver 404 coupled to the antenna 402. The transceiver 404 can be a wireless transceiver at the node 400 and can communicate bi-directionally with base stations or other UEs. For example, the transceiver 404 can receive and transmit wireless signals from and to a base station via downlink / uplink communications. The transceiver 404 can also receive and transmit wireless signals from and to another UE via sidelink communications. The transceiver 404 can include a modem to modulate the packets and provide the modulated packets to the antenna 402 for transmission, and to demodulate packets received from the antenna 402.

[0072] The node 400 can include a memory 406. The memory 406 can be any type of computer-readable storage medium, including volatile or nonvolatile memory devices, or a combination thereof. Computer-readable storage media include, but are not limited to, non-transitory computer-readable media. Non-transitory storage media can be accessed by a general purpose or special purpose computer. Examples of non-transitory storage media include, but are not limited to, portable or fixed computer disks, hard disks, random access memory (RAM), erasable programmable read-only memory (EPROM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), digital versatile disks (DVDs), flash memory, compact diskettes (CD-ROMs), or other optical and magnetic storage devices. Non-transitory media can be used to carry or store desired program code means (e.g., instructions and / or data structures) and can be accessed by a general purpose or special purpose computer, or a general purpose or special purpose processor. In some examples, software / code can be transmitted from a remote source (e.g., a website, server, etc.) using coaxial cable, fiber optic cable, twisted pair cable, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave. In such examples, the coaxial cable, fiber optic cable, twisted pair cable, DSL, or wireless technologies such as infrared, radio, and microwave are within the definition of medium. Combinations of the above examples are also within the scope of computer-readable media.

[0073] Memory 406 can store information related to the identification of node 400 as well as signals and / or data received by antenna 402. Memory 406 can also store post-processed signals and / or data. Memory 406 can also store computer-readable program instructions, mathematical models, and algorithms used in signal processing in transceiver 404 and computations in processor 408. Memory 406 can also store computer-readable program instructions for execution by processor 408 to operate node 400 to perform various functions described in the present disclosure. In some examples, memory 406 can include a Basic Input / Output System (BIOS) that can control basic hardware or software operation such as the interaction with peripheral components or devices. In some embodiments, node 400 is a Type A UE and memory 406 includes both an LTE SL module and an NR SL module. In some embodiments, node 400 is a Type B UE and memory 406 includes only an NR SL module. In some embodiments, node 400 is a Type C UE and memory 406 includes only an LTE SL module.

[0074] Computer readable program instructions can be in assembly code, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language and conventional procedural programming languages. The computer readable program instructions can execute entirely on the user's computing device, partly on the user's computing device, as a stand-alone software package, partly on the user's computing device and partly on a remote computing device or entirely on the remote computing device or server. In the latter scenario, the remote computing device can be connected to the user's computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computing device

[0075] The node 400 can include a processor 408, which can include a hardware device that has a processing capability. The processor 408 can include at least one of a general-purpose processor, a Digital Signal Processor (DSP), a Central Processing Unit (CPU), a microcontroller, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or other programmable logic device. Examples of the general-purpose processor include, but are not limited to, a microprocessor, any conventional processor, a controller, a microcontroller, or a state machine. In some embodiments, the processor 408 can be implemented using a combination of devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. The processor 408 can receive a downlink signal or a sidelink signal from the transceiver 404 and further process the signal. The processor 408 can also receive data packets from the transceiver 404 and further process the packets. In some embodiments, the processor 408 can be configured to operate memory using a memory controller. In some embodiments, the memory controller can be integrated into the processor 408. The processor 408 can be configured to execute computer-readable instructions stored in memory (e.g., the memory 406) to cause the node 400 to perform various functions.

[0076] The node 400 can include a Global Positioning System (GPS) 410. The GPS 410 can be used to enable location-based services or other services based on a geographical location of the node 400, and / or synchronization between UEs. The GPS 410 can receive Global Navigation Satellite Systems (GNSS) signals from a single satellite or multiple satellite signals via the antenna 402 and provide a geographical location (e.g., coordinates) of the node 400.

[0077] The node 400 can include an input / output (I / O) device 412, which can be used to communicate results of signal processing and computations to a user or other devices. The I / O device 412 can include a user interface including a display and input devices for transmitting user commands to the processor 408. The display can be configured to display status of signal reception at the node 400, data stored at the memory 406, status of signal processing, and results of computations, etc. The display can include, but is not limited to, a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), a Light-Emitting Diode (LED), a plasma gas display, a touch screen, or other image projection device for displaying information to a user. The input devices can be any type of computer hardware device for receiving data and control signals from a user. The input devices can include, but are not limited to, a keyboard, a mouse, a scanner, a digital camera, a joystick, a trackball, cursor direction keys, a touch screen monitor, or an audio / video commander, etc.

[0078] The node 400 can also include a bus 414, such as an electrical bus connecting the transceiver 404, the memory 406, the processor 408, the GPS 410, and the I / O device 412.

[0079] In some embodiments, the node 400 can be configured or programmed for sidelink communication. The processor 408 can be configured to execute instructions stored in the memory 406 to perform carrier aggregation in sidelink communication consistent with the method 200 described in connection with Figure 2 or to perform carrier correlation detection consistent with the method 300 described in connection with Figure 3

[0080] In embodiments where the node 400 is a Type A UE, the node 400 can include a first radio access technology (RAT1) module 420 in communication with the bus 414 and a second radio access technology (RAT2) module 422 in communication with the bus 414. In some embodiments, the RAT1 module 420 can be configured to implement a first RAT, such as LTE. In some embodiments, the RAT2 module 422 can be configured to implement a second RAT different from the first RAT, such as NR. Note that the types of RATs implemented by the RAT modules 420, 422 are not limited to LTE and NR. The RAT modules 420, 422 can implement any type of RAT without changing the principles of operation of the embodiments described herein.

[0081] ​In embodiments where the node 400 is a Type B UE or a Type C UE, the node 400 can include only one RAT module (e.g., RAT1 module 420). The RAT1 module 420 can implement any type of RAT, such as LTE, NR, or other types of RATs. In Figure 4 In some embodiments, the RAT2 module 422 can not be included.

[0082] Any of the embodiments described in this disclosure can be applied to 3GPP sidelink. For example, this can be applied to Release 18 NR sidelink and / or Release 18 LTE-NR sidelink coexistence (e.g., sidelink for unlicensed access). However, the embodiments described in this disclosure are not limited to such technologies, but can also be applied to other wireless communication technologies, such as and not limited to Digital Enhanced Cordless Telecommunications / Digital European Cordless Telecommunications (DECT) or IEEE 802.11, such as Wi-Fi.

[0083] As used in this disclosure, the use of the term “or” in a list of items indicates an inclusive list. The list of items can be prefixed with a phrase such as “at least one of” or “one or more of.” For example, a list of A, B, or C includes A or B or C or AB (i.e., A and B) or AC or BC or ABC (i.e., A and B and C). Also, as used in this disclosure, a phrase referring to “based on” should not be construed as meaning “based only on” a set of conditions, but rather “based at least in part on” the set of conditions. For example, a result described as “based on condition A” can be based on both condition A and condition B without departing from the scope of this disclosure.

[0084] In this specification, the terms “comprise,” “contain,” or “include,” can be used interchangeably and have the same meaning, and are interpreted to be inclusive and open-ended. The terms “comprise,” “contain,” or “include” can be used before an element list, and mean that at least all the listed elements are present, but other elements not in the list can also be present. For example, if A includes B and C, then {B, C} and {B, C, D} are both within the scope of A.

[0085] The present disclosure describes example configurations that are not intended to represent all examples that can be implemented or all configurations within the scope of the present disclosure. The term "exemplary" should not be construed as "preferred" or "advantageous" over other examples, but rather "illustrative, example, or exemplary." From reading the present disclosure, including the description of the embodiments and the drawings, those skilled in the art will be able to contemplate changes in form and detail of the techniques described herein that can be made without departing from the spirit and scope of the techniques described. Those skilled in the art will appreciate that the embodiments described herein or certain features thereof can be combined with other embodiments or certain features thereof to result in yet further embodiments that fall within the scope of the techniques described herein. Accordingly, the present disclosure is not intended to be limited to the examples described herein but rather is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0086] The flow diagrams and the block diagrams in the drawings are examples of architectures, functionality, and operations that might be implemented in systems, methods, and apparatuses according to various embodiments. It should be noted that in some alternative implementations, the functions noted in the blocks might occur out of the order noted in the figures. For example, two blocks noted in succession might actually be executed substantially concurrently or the blocks might sometimes be executed in the reverse order, depending upon the functionality involved. As will be understood by those skilled in the art, such methods might include additional or fewer steps, and the steps might be arranged in a different order.

[0087] It should be understood that the described embodiments are not mutually exclusive, and elements, components, materials or steps described in connection with one example embodiment can be combined with or eliminated from other embodiments in a suitable manner to achieve a desired design purpose.

[0088] Reference herein to "some embodiments" or "some example embodiments" means that a particular feature, structure, or characteristic described in connection with an embodiment can be included in at least one embodiment. Appearances of the phrase "one embodiment," "some embodiments," or "another embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily all referring to a single, alternative embodiment, or a particular series of embodiments.

[0089] Furthermore, the use of the terms "a" and "an" to describe singular entities should be understood to mean "one or more" in general, unless otherwise indicated by the context or explicitly stated otherwise.

[0090] Unless specifically stated otherwise, each numerical value and range should be interpreted as approximately as the context and state of art permits, with the word "approximately" or "about" preceding a numerical value or range generally indicating that deviations of up to 1%, unless otherwise stated or indicated by context.

[0091] Although elements in method claims, if any, are recited in a particular order all that it means is that the elements will be carried out, preferably, in that order. No inference should be drawn regarding a dependency or the requirements for any particular order for carrying out elements therein.

[0092] It will be understood that certain features of the disclosure, which are, for clarity, described in the context of separate embodiments, can also be provided in combination in a single embodiment. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single embodiment, can also be provided separately or in any suitable

[0093] It will be further understood that various modifications, alternatives, and variations of the details of the components described and illustrated for the purpose of explanation have been described and illustrated in the context of the embodiments described. Accordingly, the claims appended hereto cover all such alternatives, modifications and variations as fall within the scope of the aspects of the claims.

[0094] Clause 1 : A method for carrier aggregation in sidelink communications, comprising: determining, at a first node, a set of candidate carriers for aggregation; selecting, from the set of candidate carriers, one or more candidate carriers as one or more component carriers for carrier aggregation based on a correlation between the carriers; and transmitting or receiving on the one or more component carriers.

[0095] Clause 2: The method of clause 1, further comprising: performing the selecting based on excluding one or more carriers having a high correlation with another one or more carriers.

[0096] Clause 3: The method of clause 2, further comprising: determining the correlation between the carriers based on correlation information received at the first node.

[0097] Clause 4: The method of clause 3, further comprising: receiving a communication including the correlation information from a second node, wherein the communication comprises any of a radio interface message, a radio protocol data unit header, a physical layer field, or physical layer control information.

[0098] Clause 5: The method of clause 1, further comprising: performing a carrier correlation detection procedure.

[0099] Clause 6: The method of clause 5, wherein the carrier correlation detection procedure is performed upon receipt, by the first node, of an indication to start the carrier correlation detection procedure.

[0100] Clause 7: The method of clause 6, wherein the indication comprises information related to a set of second carriers for which the first node is allowed to perform carrier correlation detection on the set of second carriers.

[0101] Clause 8: The method of clause 6, further comprising: receiving, from a second node, a communication comprising an indication to start the carrier correlation detection procedure, wherein the communication comprises any of a radio interface message, a radio protocol data unit header, a physical layer field, or physical layer control information.

[0102] Clause 9: The method of clause 5, further comprising: restarting the carrier correlation detection procedure.

[0103] Clause 10: The method of clause 9, wherein the restarting is triggered based on an event detected by the first node.

[0104] Clause 11: The method of clause 10, wherein the event comprises one or more of: a change in a traffic metric; a change in the traffic metric over a predetermined time period; a change in the traffic metric over the predetermined time period that exceeds a configured or preconfigured threshold; a change in a plurality of traffic metrics; a change in the plurality of traffic metrics over the predetermined time period; or a change in the plurality of traffic metrics over the predetermined time period that each exceed the configured or preconfigured threshold.

[0105] Clause 12: The method of clause 11, wherein the traffic metric comprises one or more of a received signal strength indicator or a channel busy ratio.

[0106] Clause 13: The method of clause 11, wherein the predetermined time period begins at the start of the carrier correlation detection procedure.

[0107] Clause 14: The method of clause 11, wherein the predetermined time period is scaled depending on a speed of the first node or a rate of observed changes in a radio environment.

[0108] Clause 15: The method of clause 5, further comprising: start a timer when the carrier correlation detection procedure starts; and restart the carrier correlation detection procedure when the timer expires.

[0109] Clause 16: The method of clause 15, wherein a duration of the timer is based on any of: a stored configuration in the first node provided by a controlling network entity; a stored configuration in the first node provided by another node; a pre-configuration in a subscriber identity unit; a pre-configuration in a universal integrated circuit card; or a hardcoding in the first node.

[0110] Clause 17: A first node for performing carrier aggregation in sidelink communications, comprising: a memory configured to store instructions; and a processor configured to execute the instructions stored in the memory to: determine a set of candidate carriers for aggregation; select one or more candidate carriers from the set of candidate carriers as one or more component carriers for carrier aggregation based on a correlation between carriers; and transmit or receive on the one or more component carriers.

[0111] Clause 18: The first node of clause 17, wherein the processor is further configured to: perform the selection based on excluding one or more carriers having a high correlation with another one or more carriers.

[0112] Clause 19: The first node of clause 18, wherein the processor is further configured to: determine the correlation between carriers based on correlation information received at the first node.

[0113] Clause 20: The first node of clause 19, wherein the processor is further configured to: receive a communication including the correlation information from a second node, wherein the communication includes any of a radio interface message, a radio protocol data unit header, a physical layer field, or physical layer control information.

[0114] Clause 21: The first node of clause 17, wherein the processor is further configured to: perform a carrier correlation detection procedure.

[0115] Clause 22: The first node of clause 21, wherein the performing the carrier correlation detection procedure is performed upon receiving, by the first node, an indication to start the carrier correlation detection procedure.

[0116] Clause 23: The first node of clause 22, wherein the indication comprises information related to a set of second carriers for which the first node is allowed to perform carrier correlation detection on the set of second carriers.

[0117] Clause 24: The first node of clause 22, wherein the processor is further configured to: receive the indication as a communication from a second node, and the communication comprises any of a radio interface message, a radio protocol data unit header, a physical layer field, or physical layer control information.

[0118] Clause 25: The first node of clause 21, wherein the processor is further configured to: restart the carrier correlation detection procedure.

[0119] Clause 26: The first node of clause 25, wherein the restarting is triggered based on an event detected by the first node.

[0120] Clause 27: The first node of clause 26, wherein the event comprises one or more of: a change in a traffic metric; a change in the traffic metric over a predetermined time period; a change in the traffic metric over the predetermined time period that exceeds a configured or preconfigured threshold value; a change in a plurality of traffic metrics; a change in the plurality of traffic metrics over the predetermined time period; or a change in the plurality of traffic metrics that each exceed the configured or preconfigured threshold value over the predetermined time period.

[0121] Clause 28: The first node of clause 27, wherein the traffic metric comprises one or more of a received signal strength indicator or a channel busy ratio.

[0122] Clause 29: The first node of clause 27, wherein the predetermined time period starts at the start of the carrier correlation detection procedure.

[0123] Clause 30: The first node of clause 27, wherein the predetermined time period is scaled depending on a speed of the first node or a rate of observed changes in a radio environment.

[0124] Clause 31 : The first node of clause 21, wherein the processor is further configured to: start a timer when the carrier correlation detection procedure starts; and restart the carrier correlation detection procedure when the timer expires.

[0125] Clause 32: The first node of clause 31, wherein a duration of the timer is based on any of: a stored configuration in the first node provided by a controlling network entity; a stored configuration in the first node provided by another node; a pre-configuration in a subscriber identity unit; a pre-configuration in a universal integrated circuit card; or a hardcoding in the first node.

[0126] Clause 33: A non-transitory computer-readable medium storing instructions executable by one or more processors of a first node in a communication network to perform a method comprising: determining, at the first node, a set of candidate carriers for aggregation; selecting, from the set of candidate carriers, one or more candidate carriers as one or more component carriers for carrier aggregation based on a correlation between the carriers; and transmitting or receiving on the one or more component carriers.

[0127] Clause 34: A method for carrier correlation detection comprising: determining a correlation of signals between carriers in a set of carriers; creating a resource matrix for each carrier in the set of carriers; and obtaining a correlation metric based on the resource matrix.

[0128] Clause 35: The method of clause 34, further comprising: receiving one or more signals in the set of carriers, wherein the one or more signals comprise a predetermined payload or a reference signal.

[0129] Clause 36: The method of clause 35, wherein the predetermined payload comprises any of: a stored configuration in a first node provided by a controlling network entity; a stored configuration in the first node provided by another node; a pre-configuration in a subscriber identity unit; a pre-configuration in a universal integrated circuit card; or Hardcoding in the first node.

[0130] Clause 37: The method of clause 35, wherein the reference signal comprises any of: a channel state information reference signal; or a demodulation reference signal with one of a physical sidelink control channel or a physical sidelink shared channel.

[0131] Clause 38: The method of clause 34, wherein determining the correlation of the signal is based on any of: received energy; a channel impulse response; a history of channel busy ratio measurements; a history of received signal strength indicator measurements; a history of reserved resources; a history of channel occupancy ratio measurements; a history of channel state information report values; a history of L3 filtered sidelink received signal reference power measurements; a history of one or more of an acknowledgement ratio or a negative acknowledgement ratio; a listen before talk (LBT) failure rate; a history of persistent LBT failures; a history of radio link failures; or a history of one or more of beam recovery or beam realignment.

[0132] Clause 39: The method of clause 34, wherein creating the resource matrix comprises creating a time and frequency resource matrix based on sensing information determined by the first node.

[0133] Clause 40: The method of clause 34, wherein: obtaining the correlation measure comprises calculating the correlation measure using a binary matrix; and each matrix element of the resource matrix consists of binary information if activity is detected or not detected at the first node in each of one or more of time resources or frequency resources.

[0134] Clause 41: The method of clause 40, wherein whether activity is detected at the first node is based on any one or more of: received signal reference power; received signal strength indicator; signal to noise and interference ratio; or energy detection.

[0135] Clause 42: The method of clause 41, further comprising: comparing a measured value of each of one or more of time resources or frequency resources to a threshold value, wherein: if the measured value is below the threshold value, the matrix element for the corresponding resource is a “0” value; and if the measured value is equal to or above the threshold value, the matrix element for the corresponding resource is a “1” value.

[0136] Clause 43: The method of clause 42, wherein the threshold value comprises any of: a stored configuration in the first node provided by a controlling network entity; a stored configuration in the first node provided by another node; a pre-configuration in a subscriber identity unit; a pre-configuration in a universal integrated circuit card; or a hard-coding in the first node.

[0137] Clause 44: The method of clause 34, wherein: obtaining the correlation measure comprises: using a binary matrix to compute the correlation measure, and each matrix element of the resource matrix consists of identification information to provide information about time and frequency resources in which a first node is able to receive a signal from a second node and identify its carrier.

[0138] Clause 45: The method of clause 34, wherein: obtaining the correlation measure comprises: using a numerical matrix to compute the correlation measure, and each matrix element of the resource matrix identifies a correlation of a signal transmitted in time and frequency resources.

[0139] Clause 46: The method of clause 45, wherein each matrix element is an integer value or a floating point value.

[0140] Clause 47: The method of clause 45, wherein each matrix element is a correlation value obtained based on a similarity of channel impulse responses of different carriers.

[0141] Clause 48: The method of clause 34, wherein obtaining the correlation measure comprises: computing the correlation measure based on a result of decoding data that has been replicated across multiple carriers in the set of carriers.

[0142] Clause 49: The method of clause 48, wherein: High values in the matrix indicate high correlation between carriers; and Low values in the matrix indicate low correlation between carriers.

[0143] Clause 50: The method of clause 34, further comprising: receiving the correlation metric at the first node from the second node.

[0144] Clause 51 : The method of clause 50, wherein the receiving comprises any of: populating a radio parameter, indicator, or field in a radio interface message; populating a field in a radio protocol data unit header; populating a physical layer field; or receiving an octet string contained in a radio protocol.

[0145] Clause 52: The method of clause 50, wherein the receiving comprises receiving the correlation metric as a matrix or a compressed matrix.

[0146] Clause 53: The method of clause 50, wherein the receiving comprises receiving the correlation metric as an integer value or a floating point number represented as a codepoint in a fixed size bit combination.

[0147] Clause 54: The method of clause 50, wherein the receiving comprises receiving the correlation metric as a single bit to indicate whether or not carriers are correlated.

[0148] Clause 55: The method of clause 54, further comprising: comparing the correlation metric to a threshold to determine a value of the single bit; and setting the value of the single bit to “1” if the correlation is above the threshold.

[0149] Clause 56: The method of clause 34, further comprising: sharing the correlation metric from the first node to the second node.

[0150] Clause 57: The method of clause 56, wherein the sharing comprises any of: populating a radio parameter, indicator, or field in a radio interface message; populating a field in a radio protocol data unit header; populating a physical layer field; or sending an octet string contained in a radio protocol.

[0151] Clause 58: The method of clause 56, wherein the sharing comprises sharing the correlation metrics as a matrix or a compressed matrix.

[0152] Clause 59: The method of clause 56, wherein the sharing comprises sharing the correlation metrics as integer values or floating point numbers represented as code points in a fixed size bit combination.

[0153] Clause 60: The method of clause 56, wherein the sharing comprises sharing the correlation metrics as a single bit to indicate whether a carrier is correlated.

[0154] Clause 61 : The method of clause 60, further comprising: comparing the correlation metrics to a threshold to determine a value of the single bit; and setting the value of the single bit to “1” if the correlation is above the threshold.

[0155] Clause 62: The method of clause 34, further comprising: if the correlation metrics indicate that one or more carriers are strongly correlated, indicating that one or more of the carriers are excluded from a transmission occasion.

[0156] Clause 63: The method of clause 34, further comprising: determining carriers having a correlation value below a threshold; and sharing the determined carriers with a second node.

[0157] Clause 64: A first node for performing carrier correlation detection, comprising: a memory configured to store instructions; and a processor configured to execute the instructions stored in the memory to: determine a correlation of signals between carriers in a set of carriers; create a resource matrix for each carrier in the set of carriers; and obtain a correlation metric based on the resource matrix.

[0158] Clause 65: The first node of clause 64, wherein: the processor is further configured to receive one or more signals in the set of carriers; and the signals comprise a predetermined payload or a reference signal.

[0159] Clause 66: The first node of clause 65, wherein the predetermined payload comprises any of: the stored configuration in the first node provided by a control network entity; the stored configuration in the first node provided by another node; a pre-configuration in a subscriber identity unit; a pre-configuration in a universal integrated circuit card; or a hard-coding in the first node.

[0160] Clause 67: The first node of Clause 65, wherein the reference signal comprises any of: a channel state information reference signal; or a demodulation reference signal with a physical sidelink control channel or a physical sidelink shared channel.

[0161] Clause 68: The first node of Clause 64, wherein determining the correlation of the signal is based on any of: a received energy; a channel impulse response; a history of channel busy ratio measurements; a history of received signal strength indicator measurements; a history of reserved resources; a history of channel occupancy ratio measurements; a history of channel state information report values; a history of L3 filtered sidelink received signal reference power measurements; a history of acknowledgement / negative acknowledgement ratios; a listen before talk (LBT) failure rate; a history of persistent LBT failures; a history of radio link failures; or a history of beam recovery / beam realignment.

[0162] Clause 69: The first node of Clause 64, wherein the processor is further configured to create the resource matrix by creating a time and frequency resource matrix based on sensing information determined by the first node.

[0163] Clause 70: The first node of Clause 64, wherein: the processor is further configured to obtain the correlation measure by: each matrix element of the resource matrix consists of binary information if activity is detected or not detected at the first node in each of one or more of time resources or frequency resources.

[0164] Clause 71 : The first node of clause 70, wherein whether activity is detected at the first node is based on any one or more of: a received signal reference power; a received signal strength indicator; a signal to noise and interference ratio; or energy detection.

[0165] Clause 72: The first node of clause 71, wherein the processor is further configured to: compare a measured value of each of one or more of a time resource or a frequency resource to a threshold value, wherein: if the measured value is below the threshold value, the matrix element for the corresponding resource is a “0” value; and if the measured value is equal to or above the threshold value, the matrix element for the corresponding resource is a “1” value.

[0166] Clause 73: The first node of clause 72, wherein the threshold value comprises any one of: a stored configuration in the first node provided by a controlling network entity; a stored configuration in the first node provided by another node; a pre-configuration in a subscriber identity unit; a pre-configuration in a universal integrated circuit card; or a hardcoding in the first node.

[0167] Clause 74: The first node of clause 64, wherein: the processor is further configured to obtain the correlation measure by: each matrix element of the resource matrix is comprised of identifying information to provide information about time and frequency resources in which the first node is able to receive signals from a second node and identify their carriers.

[0168] Clause 75: The node of clause 64, wherein: the processor is further configured to obtain the correlation measure by: each matrix element of the resource matrix identifies a correlation of signals transmitted in time and frequency resources.

[0169] Clause 76: The first node of clause 75, wherein each matrix element is an integer value or a floating point value.

[0170] Clause 77: The first node of clause 75, wherein each matrix element is a correlation value obtained based on a similarity of channel impulse responses of different carriers.

[0171] Clause 78: The first node of clause 64, wherein the processor is further configured to: obtain the correlation metric by calculating the correlation metric based on a result of decoding data that has been replicated across multiple carriers in the set of carriers.

[0172] Clause 79: The first node of clause 78, wherein: high values in the matrix indicate high correlation between carriers; and low values in the matrix indicate low correlation between carriers.

[0173] Clause 80: The first node of clause 64, wherein the processor is further configured to: receive the correlation metric from a second node.

[0174] Clause 81: The first node of clause 80, wherein the processor is further configured to receive the correlation metric by any of: populating a radio parameter, indicator, or field in a radio interface message; populating a field in a radio protocol data unit header; populating a physical layer field; or receiving an octet string contained in a radio protocol.

[0175] Clause 82: The first node of clause 80, wherein the processor is further configured to receive the correlation metric as a matrix or a compressed matrix.

[0176] Clause 83: The first node of clause 80, wherein the processor is further configured to receive the correlation metric as an integer value or a floating point number represented as a codepoint in a fixed size bit combination.

[0177] Clause 84: The first node of clause 80, wherein the processor is further configured to receive the correlation metric as a single bit to indicate whether carriers are correlated.

[0178] Clause 85: The first node of clause 84, wherein the processor is further configured to: compare the correlation metric to a threshold to determine a value of the single bit; and if the correlation is higher than the threshold, setting the value of the single bit to "1".

[0179] Clause 86: The first node of clause 64, wherein the processor is further configured to: share the correlation metric with a second node.

[0180] Clause 87: The first node of clause 86, wherein the processor is further configured to share the correlation metric by any of: populating a radio parameter, indicator, or field in a radio interface message; populating a field in a radio protocol data unit header; populating a physical layer field; or sending an octet string contained in a radio protocol.

[0181] Clause 88: The first node of clause 86, wherein the processor is further configured to share the correlation metric as a matrix or a compressed matrix.

[0182] Clause 89: The first node of clause 86, wherein the processor is further configured to share the correlation metric as an integer value or a floating point number represented as a codepoint in a fixed size combination of bits.

[0183] Clause 90: The first node of clause 86, wherein the processor is further configured to share the correlation metric as a single bit to indicate whether a carrier is correlated.

[0184] Clause 91: The first node of clause 90, wherein the processor is further configured to: compare the correlation metric to a threshold to determine a value of the single bit; and if the correlation is higher than the threshold, setting the value of the single bit to "1".

[0185] Clause 92: The first node of clause 64, wherein the processor is further configured to: if the correlation metric indicates that one or more carriers are strongly correlated, indicate that one or more of the carriers are excluded from a transmission occasion.

[0186] Clause 93: The first node of clause 64, wherein the processor is further configured to: determine carriers having a correlation value below a threshold; and share the determined carriers with a second node.

[0187] Clause 94: A non-transitory computer-readable medium storing instructions executable by one or more processors of a first node in a communication network to perform a method comprising: determining a correlation of signals between carriers in a set of carriers; creating a resource matrix for each carrier in the set of carriers; and obtaining a correlation metric based on the resource matrix.

Claims

1. A method for carrier aggregation in sidelink communication, including: At the first node, determine the set of candidate carriers for aggregation; Based on the correlation between carriers, one or more candidate carriers are selected from the candidate carrier set as one or more component carriers for carrier aggregation; and Transmission or reception is performed on one or more component carriers.

2. The method according to claim 1, further comprising: The selection is performed by excluding one or more carriers that are highly correlated with another one or more carriers.

3. The method according to claim 1, further comprising: Perform carrier correlation detection process.

4. The method according to claim 3, wherein, The carrier correlation detection process is executed when the first node receives an instruction to start the carrier correlation detection process.

5. The method according to claim 4, wherein, The indication includes information related to the second carrier set that allows the first node to perform carrier correlation detection on the second carrier set.

6. The method according to claim 3, further comprising: When the carrier correlation detection process begins, a timer is started; as well as When the timer expires, the carrier correlation detection process restarts.

7. The method according to claim 6, wherein, The duration of the timer is based on any of the following: The configuration stored in the first node, provided by the control network entity; The configuration stored in the first node is provided by another node; Pre-configuration in subscriber identity units; Pre-configuration in general-purpose integrated circuit cards; or The hard-coded first node.

8. A method for carrier correlation detection, including: Determine the correlation between signals among carriers in a carrier set; Create a resource matrix for each carrier in the carrier set; as well as Based on the resource matrix, a relevance metric is obtained.

9. The method according to claim 8, further comprising: Receive one or more signals from the carrier set, wherein the one or more signals include a predetermined payload or reference signal.

10. The method according to claim 8, wherein, The correlation of the signal is determined based on any of the following: The energy received; Channel impulse response; Historical data on channel busy ratio measurements; History of received signal strength indicator measurements; The history of reserved resources; History of channel occupancy ratio measurement; History of channel state information report values; History of L3 filter side link received signal reference power measurement; The history of one or more of the confirmation ratio or negative confirmation ratio; Listen-before-speak (LBT) failure rate; The history of continuous LBT failures; History of radio link failures; or The history of one or more of beam recovery or beam realignment.

11. The method according to claim 8, wherein, Creating the resource matrix includes: creating a time and frequency resource matrix based on the sensing information determined by the first node.

12. The method according to claim 8, wherein: Obtaining the correlation metric includes: calculating the correlation metric using a binary matrix; and If activity is detected or not detected at the first node in one or more of the time resources or frequency resources, then each matrix element of the resource matrix consists of binary information.

13. The method according to claim 8, wherein: Obtaining the correlation metric includes: calculating the correlation metric using a binary matrix, and Each element of the resource matrix consists of identification information to provide information about the time and frequency resources in which the first node is able to receive signals from the second node and identify its carrier.

14. The method according to claim 8, wherein: Obtaining the correlation metric includes: calculating the correlation metric using a numerical matrix, and Each element of the resource matrix identifies the correlation of signals transmitted in time and frequency resources.

15. The method according to claim 14, wherein, Each matrix element is a correlation value obtained based on the similarity of the channel impulse response of different carriers.

16. The method according to claim 8, wherein, Obtaining the correlation metric includes calculating the correlation metric based on the result of decoding data that has been replicated across multiple carriers in the carrier set.

17. The method of claim 8, further comprising: The correlation metric is received from the second node at the first node.

18. The method of claim 8, further comprising: The correlation metric is shared from the first node to the second node.

19. The method of claim 8, further comprising: If the correlation metric indicates that one or more other carriers are strongly correlated, then one or more of the carriers are excluded from the transmission timing.

20. The method of claim 8, further comprising: Identify carriers with correlation values ​​below a threshold; and The determined carrier is shared with the second node.

Images